1. Field of the Invention
The present disclosure generally relates to increasing left ventricular compliance. More particularly, the disclosure generally relates to systems and methods for scoring endocardium tissue.
2. Description of the Relevant Art
Left ventricular (LV) diastolic dysfunction (reduced compliance) was first identified in the 1970s as an important etiology producing shortness of breath in patients at rest and exertion, and as a major cause of hospital admission due to diastolic heart failure. Half of all heart failure admissions are due to left ventricular systolic failure (enlarged weak hearts), but half are caused by hearts with normal systolic function that are thickened with diastolic dysfunction. Despite 40 years developing solutions to improve left ventricular diastolic compliance, there have been no mediations or therapies invented which can acutely and permanently increase compliance. Medications which reduce calcium availability to the myocytes have not successfully improved diastolic compliance. As a result, medications are being used to slow the heart rate to prolong diastole (calcium and beta blockers), or decrease left ventricular filling pressures by moving down a fixed compliance curve with diuretics to reduce blood volume. However, there are no medications which can improve left ventricular diastolic compliance. That is because left ventricular compliance is known to be primarily related to the thickness of the left ventricular myocardium (normally 8-9 mm and increases to 12-16 mm) and the increase in the percentage of fibrosis which is known to occur as left ventricular hypertrophy develops (3% up to 12%). A genetic heart muscle condition called hypertrophic cardiomyopathy exists wherein a patient's heart can be as thick as 40 mm and the percentage of fibrosis can exceed more than 20% of the mass of the left ventricle.
The only therapeutic intervention currently available is the use of pharmacologicals to lower blood pressure in cases of left ventricular hypertrophy due to hypertension. However, although left ventricular hypertrophy can regress over months of time with normalization of blood pressure, left ventricular hypertrophy often cannot be completely normalized and often results in an increase in the percentage of fibrosis of the myocardium. Many other etiologies for left ventricular hypertrophy besides hypertension are recognized including diabetes, valvular heart disease, and hypertrophic cardiomyopathy. The relevant patient population is very large both in the U.S. (millions), and around the world.
U.S. Pat. No. 6,165,188 issued to Saadat et al. (hereinafter “Saadat”) discloses an apparatus and methods for percutaneously performing myocardial revascularization using a catheter having an end region that is directable to contact a patient's endocardium at a plurality of positions. However, Saadat does not disclose a cutting device which is conveyed along a guide system in a first conduit to score endocardium tissue. Although there exist many different types of surgical devices none of the known devices accomplish what the herein described scoring device is capable of.
Therefore a system and/or method which results in increase in left ventricular compliance is highly beneficial.